Resistance-box for electrical measurements.



I. ARONSON.

PATENTED MAY '7, 1907.

RESISTANCE BOX FOR ELECTRICAL MEASUREMENTS.

APPLICATION FILED MAR. 11, 1907.

2 SHEETS-SHEET 1.

No. 852,536.. PATENTED MAY 7, 1907. F ARONSON.

RESISTANCE BOX FOR ELECTRICAL MEASUREMENTS.

APPLICATION FILED MAR.11. 1907.

2 SHEETS-SHEET z.

M E E V 425 2r jffy FRANK ARONSON, UF- EVANSTUN, ILLINOIS.

RESISTANCE-BOX FOR ELEGTREGAL MEASU no. access.

. Specification of Letters Patent.

FEMENTSB Patented May 7, 1907.

Appli ati n fil d March 11. 1907. Serial No. 361,741.

To all whom, it may concern:

Be it known that I, FRANK ARONSON, a citizen of the United States, residing at Evanston, in the county of Cook and State of lllinois, have invented new and useful Improvements, in Resistance Boxes for Electrical Measurements, of which the following is a.

specification.

This invention relates to resistance boxes for electrical measurements and its object is to simplify and improve the construction, to reduce the cost of manufacture, and at the same time to make provision for better and more effective contacts when the plugs are inserted to cut out the coils.

Another object of the invention is to provide means of simple construction for supporting the coils in the box.

In the accompanying drawings illustrating my invention Figure 1 shows a box partly in elevation and partly in section. Fig. 2 is a transverse sectional view on the line 22 of 1. Fig. 3 is a detail plan view showing a single coil. Fig. 4 is a detail perspective view of a coil suspending plate. Fig. Eris a 1 detail view showing a single plug socket with the plug in place. Fig. 6 1s a similar view without the plug. Fig. 7 is a plan view and Fig. 8 is an elevation showing the contact plate after the first stamping operation. Fig. 9 is a plan view and Fig. 10 is an elevation of the contact plate after the second stamping operation, in completed form. I Fig. 1 1 is a detail sectional view of the upper end of the coil spool.

Referring to the drawings 12 is a-box of suitable size and shape and provided with a removable top consisting of a rubber plate 13 which carries all the parts of the invention about to bedescribed. A plurality of coils 14 are suspended from the top plate 13 within thebox, preferably in two parallel rows. A suspending plate 15 (Fig. 4) is fastened on the upper head 16 of each coil and for this purpose the plateis preferably provided with prongs 15 which' are adaptedto grasp the ead 16 and be fitted into aperipheral groove 1 6 therein. The suspending plate has an extension 17 provided with openings 17 to receive the binding screws 18 which ass through the top of the box and are provided with nuts 18 whereby the plate is securely fastened to the top. The coils are noninductively wound and are connected to the bindon-the insulating plate 13 by the binding screws 18 and these contact plates are constructed to form sockets therebetween to receive the plugs 20. There is a socket and a plug for each coil and the contact plates are preferably arranged in two rows, the plates in each row bein in alinerhent with each other longitudinal y of the top of the box.

Each contact plate is formed from a single strip of sheet metal by stamping it first to the shape shown in Figs. 7 and 8.and then to the shape shown in Figs. 9 and 10. The contact plate is provided between its endswith openings 19 to receive the binding screws 18. The ends of each contact plate are bent upward. and downward upon themselves at 21 and 22 to provide supports 23 and contacts 24. The contacts 24 are. provided with grooves 25 to form sockets for the reception of the plugs 20 and these sockets are prefer ably of conical form to accommodate the cone shaped plugs. The contacts 2 1 are inclined outwardly from the supports 23 (Fig.

.10) and the plates are arranged in such jux- 27 which can bev located at either end of the rows.

In practice the coils and all the parts connected therewith on the underside of the top of the box are preferably protected by a coating of paraifin. When a l of the lugs are in place in their sockets the coils wil 'be cut out of the circuit by reason of the short circuit established through the contact plates and plugs and. to bring a coil into the circuit its plug is removed from its socket. The coils are tested to a known resistance and the values are indicated in a suitable manner on the top of the box so that the measuring operation can be conducted in a'sirnple and expeditious manner by removing thefplugs one at a time. The contact plates are made in a sim le and inexpensive manner by stamping, as escribed, and by reason of the two bends 21 and 22 the contacts 24 are constantly supeeaeac ported in a manner to yieldingly resist the entrance of the plug whereby a perfect contact is secured. The susptuiding )lates form a simple means for connecting the coils to the plate 13 in a secure manner.

What I claim and desire to secure by Letters Pa tent is:

1. In a resistance box for electrical measurements, the combination of an insulating plate, a plurality of coils thereon, a plurality of contact plates on the insulating plate and connected in circuit with the coils, said contact plates being arranged in a row and having their ends separated and bent to form sockets therebetween, and plugs to fit in said sockets.

2. In a resistance box for electrical measurements, the combination of an'insulating plate, a plurality of coils thereon, a plurality of contact plates on the insulating plate and connected in circuit with the 'coils, said contact plates being arranged in a row and having their ends separated and bentto form yielding contacts with sockets therebetween, and plugs to lit in said sockets.

3. In a resistance box for electrical meas urements, the combination of an insulating plate, a plurality of coils thereon, a plurality of contact plates on the insulating plate and connected in circuit with the coils, said contact plates being arranged in a row with their ends separated and bent upward and downward to form at each end of the plate a yielding support and a yielding contact, there being a socket between the contacts at the ends of adjacent plates, and plugs to fit in said sockets.|

4. In a resistance box for electrical meas-' urements, the combination of an insulating plate, a plurality of coils thereon, a plurality of contact plates on the insulating plate and connected 1n circuit with the ooils, said contact plates being arranged in a row with their ends separated and bent upward to form supports and downward on said supports to form contacts, there being grooves in said contacts forming a socket between the contacts at the adjacent ends of each pair of plates, and plugs to fit in said sockets.

5. In a resistance box for electrical measurements, the combination of an insulating plate, a plurality of coils thereon, a plurality of contact plates on the insulating plate and connected in circuit with the coils, said contact plates being arranged in a row with their ends separated and each formed of a single strip of inetalplate having its ends bent upward to form supports and downward on said supports and at an inclination thereto to form contacts, there being grooves in said contacts forminga socket between the contacts at the adjacent ends of each pair of plates, and plugs to fit in said sockets.

6. In a resistance box for electrical measurements, the combination of an insulating plate, a plurality of contact plates thereon, a plurality of suspending plates on the insulatmg plate, and a plurality of coils suspended from said suspending plates and connected in circuit With said contact plates.

7. In a resistance box for electrical meas urements, the combination of an insulating plate, a plurality of contact plates thereon, a plurality of coils connected in circuit with said contact plates, the heads of said coils being provided with peripheral grooves, a plurality of suspending plates on said insulating plate, and means on said suspending plates to enter said grooves and fasten the coils to the suspending plates.

FRANK ARONSON. Witnesses:

A. H. MCCONNELL, GEO. W. SonnEL. 

